Potato chips were originally prepared on a batch basis with the hand cut potato slices immersed in a kettle of hot cooking oil and cooked until they achieved a desired appearance, at which time the chips were removed from the cooking oil and allowed to drain.
With the increased popularity of potato chips and the commensurate increase in demand for this product, processes and equipment were developed to prepare potato chips on a continuous basis and thereby increase production volumes.
Demand for potato chips continues to increase and is met for the most part by chips prepared on a continuous basis. However, there has also, more recently, been an increased demand for so-called "kettle cooked" chips which have the appearance and flavor of chips cooked by the old-fashioned batch process.
Obviously, the same problem exists today with respect to batch-prepared potato chips that existed with the original introduction of potato chips, i.e., batch production is slow, which results in both an increased price for the batch-prepared product and insufficient volume to meet demand.
It should be noted that in the production of potato chips on a continuous basis using more or less conventional equipment and processes, raw potatoes are first peeled and then sliced and the resulting slices washed, usually with water, to remove the starch which is released during the cutting process and coats the potato slices, and the washed slices are then dropped in a fryer containing a continuous stream of heated cooking oil at a temperature of approximately 325.degree. to 375.degree. F.
In the ensuing cooking process moisture is released from the slices and replaced to some extent by the cooking oil, so that the final product will have an oil content of approximately 35% to 45% by weight and a moisture content of approximately 1.5% to 2.2% by weight.
U. S. Pat. No. 4,503,127 discloses a method of preparing potato chips which eliminates the step of washing the starch-coated potato slices, and instead conveys the unwashed slices into a bath of oil or water having a temperature below the gelatinization temperature of the starch on the slices, e.g., between 122.degree. to 140.degree. F., then cooling the thus treated potato slices to at least 104.degree. F. and preferably 90.degree. F., and thereafter frying the cooled slices in vegetable oil at a temperature of 365.degree. F. The product prepared in this manner is said to be uniform in texture and appearance, less oily and contain more food solids than similar products prepared by traditional methods.
The Background of the Invention section of U.S. Pat. No. 4,503,127 also discusses several prior art patents, namely, U. S. Pat. Nos. 2,091,675; 2,179,035; 2,611,705; 3,223,024; 3,402,059; 3,997,678; 4,068,572; 4,251,895; 4,272,554; 4,277,510; 4,283,425; 4,283,437; 4,392,420; and Re. 27,531, the disclosures of which are incorporated herein by reference.
However, none of the above-noted patents are concerned with the preparation of kettle cooked chips, let alone preparation of chips of this type on a continuous basis.